

1819.] Scientific Intelligence. 73 



X. Some Corrections and Additions to Mr. Rice's Paper on the 



Weight of a Cubic Inch of distilled Water, contained in the 



Number for May of the Annals of Philosophy. By Mr. Rice. 



(To Dr. Thomson.) 

 SIR, Dublin, May 10, 1819. 



In my paper " On the Weight of a Cubic Inch of Distilled 

 Water, and the Specific Gravity of Atmospheric Air" ; inserted 

 in the Annals of Philosophy for this month, I find that, in com- 

 puting the weight of a cubic inch of water from Sir George 

 Shuckburgh's experiments, I have committed a mistake, which, 

 though trifling in its consequence, demands particular notice. 

 You will do me a great favour by giving a place to the following 

 errata and observations, if possible, in your next number. 



I am, Sir, your obedient servant, 



E. S. M. Rice. 



Page 342, line 12, for 64° read 66-4° ; line 26, for actually 

 less value, read actually greater value ; line 29, for subtracted, 

 read added. 



In consequence of these alterations, it is evident that a few of 

 the subsequent numbers will require correction. 



The signs prefixed to the numbers indicating " the corrections 

 to be made for error from buoyancy," should be positive instead 

 of negative: hence the mean deduced in line 10, should be 

 28722-4611; line 16, for 28672-7427, read 28672-8958 ; line 17, 

 the same ; also/or 252-580, read 252-582 ; line 28,/or 252-529, 

 read 252-531. A bare inspection will show the alterations to be 

 made in the other numbers. 



On the Proportion of Oxygen in Air. — Estimating the specific 

 gravities of oxygen and nitrogen in relation to air, as 1-1111 and 

 0*9722 : 1, and air to water as 0*0012085 : 1, we find atmo- 

 spheric air composed of four volumes nitrogen and one volume 

 oxygen, or 



0-8 volumes nitrogen 0-0002685 

 0-2 volumes oxygen 0-0009400 



1-0 0-0012085 



Under the idea of this being the true composition, Dr. Prout 

 adopted the specific gravities for oxygen as here given; subse- 

 quent experiments have confirmed its accuracy ; and I think the 

 trials hitherto made by the voltaic eudiometer cannot be consi- 

 dered as sufficiently precise to disprove the supposition on which 

 it was calculated. 



Chaptal, in his Chemistry, iii. 210, English translation, from 

 analyses of air by detonation with hydrogen, rates the oxygen at 

 20 per cent. Mr. Dalton mixed 100 volumes of air with 60 

 volumes of hydrogen, and fired by the electric spark, the absorp 

 tion indicated the presence of 20 volumes oxygen; the residue 

 contained none. — (Nicholson's Journal, xiii. 434.) 

 5 



